[CMake] Problems to use TRY_COMPILE

[Bill Hoffman]

Vitor Vasconcelos Araujo Silva wrote:

> 
>  >> TRY_COMPILE(RESULT ${PROJECT_BINARY_DIR}
>  >>
>  >> ${PROJECT_SOURCE_DIR}/teste.cpp
>  >> CMAKE_FLAGS
>  >> COMPILE_DEFINITIONS -I${QT_INCLUDE_DIR}
>  >>                 -I${QT_QTCORE_INCLUDE_DIR}
>  >>                      -l${QT_QTCORE_LIBRARY}
>  >> OUTPUT_VARIABLE MY_OUT
>  >> )
>  >>
>  > You are missing LINK_LIBRARIES from Qt.  I don't see where you are
>  > passing a link parameter in??
>  >
>  > -Bill
> 
>    And, after the TRY_COMPILE block I finish my CMakeLists defining the
> which libraries I want to link to my application.
> 
>    TARGET_LINK_LIBRARIES ( ${QT_EXECUTABLE_NAME}
>               ${QT_QTCORE_LIBRARY}
>               ${QT_QTGUI_LIBRARY}
>               )
> 
>    Thanks in advance,
> 
See the docs for try_compile:
http://www.cmake.org/HTML/cmake-2.6.html#command_try_compile
....
Some extra flags that can be included are, INCLUDE_DIRECTORIES, 
LINK_DIRECTORIES, and LINK_LIBRARIES. COMPILE_DEFINITIONS are 
-Ddefinition that will be passed to the compile line. try_compile 
creates a CMakeList.txt file on the fly that looks like this:

   add_definitions( <expanded COMPILE_DEFINITIONS from calling cmake>)
   include_directories(${INCLUDE_DIRECTORIES})
   link_directories(${LINK_DIRECTORIES})
   add_executable(cmTryCompileExec sources)
   target_link_libraries(cmTryCompileExec ${LINK_LIBRARIES})
....

You have this:

TRY_COMPILE(RESULT ${PROJECT_BINARY_DIR}
 >  >>
 >  >> ${PROJECT_SOURCE_DIR}/teste.cpp
 >  >> CMAKE_FLAGS
 >  >> COMPILE_DEFINITIONS -I${QT_INCLUDE_DIR}
 >  >>                 -I${QT_QTCORE_INCLUDE_DIR}
 >  >>                      -l${QT_QTCORE_LIBRARY}
 >  >> OUTPUT_VARIABLE MY_OUT
 >  >> )

You need to add:

  LINK_LIBRARIES ${QT_QTCORE_LIBRARY}
               ${QT_QTGUI_LIBRARY}

To the TRY_COMPILE call that you have.

-Bill